NFT: Home Owners - Spray Foam Insulation

How much more would he charge you for the 2" of spray foam and 4" of standard?

I have heard good reviews on the spray foam and the energy savings compared to the fiberglass. I would be curious to see how it holds up over time, because this is a fairly "new" concept, right?

but likely $3k for the entire house - all walls and attic joists. The way research say you can save between 15%-20% on utilities each year with upgraded spray foam. So if i'm spending $250 per month on gas/electric on the low end I'd save $450 per year which means I'd get my money back after 6/7 years. On the high end maybe 5. When I price it against what solar costs, it seems like a no-brainer and something I can really only do now before drywall vs. doing solar any time I want in the future.

inches when I built my house and the R19 on top of that. Each inch of spray foam if I remember correctly gives a R7 value however it is amazing sealing every gap. I also did my entire sill plate in the basement but did between 3-4 inches in those cavities. I regret not spending the extra at the time and doing my garage as well.

This guy is a very high end home builder in Austin and obsessive about building science and in particular sealing the envelope.

The process is called flash and batt. This example uses Rockwool/Stonewool which is great upgrade if you can swing it. Not only because of fire retardation but it's a superior soundproofing product as well.

https://www.youtube.com/watch?v=RyFcsoLlNSo

an additional $3k from what standard fiberglass would cost

In comment 14475517 Joeguido said:

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inches when I built my house and the R19 on top of that. Each inch of spray foam if I remember correctly gives a R7 value however it is amazing sealing every gap. I also did my entire sill plate in the basement but did between 3-4 inches in those cavities. I regret not spending the extra at the time and doing my garage as well.

The gap sealing is the huge benefit. I didn't realize how important airflow prevention was until I watched a few videos and read a couple studies. My last house had horrendous insulation, you can almost feel the air coming through the walls in the dead of winter. Awful, and not doing that again.

on spray, the lack of flexibility for changing something in the walls? For instance, if you were to add an outlet along the wall. Wouldn't you then have to remove the whole section of spray insulation in each portion of the wall as opposed to just removing sheet rock with fiberglass insulation.

but may not be the case with just doing 2" of foam. I'm also picking out all my outlet locations so I'm going to hopefully have that all covered upfront and won't need to think about it again regardless of insulation.

In comment 14475519 Ryan said:

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This guy is a very high end home builder in Austin and obsessive about building science and in particular sealing the envelope. The process is called flash and batt. This example uses Rockwool/Stonewool which is great upgrade if you can swing it. Not only because of fire retardation but it's a superior soundproofing product as well. https://www.youtube.com/watch?v=RyFcsoLlNSo

Haha, I knew it would be his channel. I haven't built any homes since before I was old enough to buy alcohol, but I still end up watching a ton of his videos.

In comment 14475527 UConn4523 said:

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In comment 14475517 Joeguido said: Quote: inches when I built my house and the R19 on top of that. Each inch of spray foam if I remember correctly gives a R7 value however it is amazing sealing every gap. I also did my entire sill plate in the basement but did between 3-4 inches in those cavities. I regret not spending the extra at the time and doing my garage as well. The gap sealing is the huge benefit. I didn't realize how important airflow prevention was until I watched a few videos and read a couple studies. My last house had horrendous insulation, you can almost feel the air coming through the walls in the dead of winter. Awful, and not doing that again.

For sure....I built my house in 2014 and I live in upstate NY where it is cold and I can heat it only using around 800-900 gallons of propane. My house is 3300 sq feet not counting the basement which is another 1300 sq feet which is finished and heated, and my bar is 600 sq feet and it's heated. Before I built this house I spent almost the same to heat a older house I was renting. I recommend spending the money up front to all my friends when they build.

Budget drives a lot if items. Spray foam is worth while invest verses fiberglass. It seal all the cracks and joints so much better. The current train of thought in the industry, is to make you home positive with pressure, which is pushing outward. The exterior humid air, here in the low country of SC have high humidity, a good part of year. We want to keep that moisture outside of the home, and should it try to get in, it is meet with a vapor barrier.

I would consider doing the entire wall cavity. This will also help seal electrical outlets, switches, conduit and etc...

One thing to discuss with our builder if you add the full wall cavity. You will need to ensure your HVAC unit is balanced for your home. Your current system might now be to large and the compressor will not fully cycle on and dry out any humidity. It is not unheard of that a make up air system needs to be installed because the house becomes so tight, no external air gets air. Thus you are breathing in recycled air and at some point you need fresh air. This is not a huge issue but something to be aware of.

I would second the idea of using spray foam. I believe closed cell in the floor system and then open foam for walls and rafters.

Side benefit, assuming out interior air handler is in the attic. Spray the rafters and not the ceiling joists. Then your air handler and ducts are inside the building envelope.
The will not be in the hot stiffling attic and air will not loos its temperature by the time it comes out of the supply vents.

foam only in the attic.

Massachusetts has a program where they do it for you at nearly no cost.

So I had it done, figuring it couldn't hurt anything. So far it hasn't hurt anything. No idea if my house is better insulated or not.

interesting, thanks for the feedback. Mechanicals will be in the basement so the attic will only consist of ducts. The current system is all getting ripped out and replaced so I’ll make sure that the new system is properly sized for the home along with the spray foam.

dampening?

The code officials I used to deal with hated spray foam. They said they'd pass me, but would always prefer fiberglass and the trade off in efficiency for letting a home breathe. Too many times with a less than perfect install they'd see trapped moisture and rot.

Make sure your guy is a real expert or you could be in trouble down the line.

I am building a house and went with spray foam. Before the interior walls were up on a windy day you would feel nothing inside. We used 2x6’s on the exterior with 2” of spray foam, leaving room if we needed to get into the walls again. We did have to add, i forget the name of it, a airblower of some sort. We had to do this because the house was so sealed up we needed to get fresh air into the house. It cost $3000. It will force out old air and pump in air from the outside. In our old house I could feel drafts from everywhere..windows, outlets, etc. These guys sealed up every crack in the house. I think on cold winter days when the wind is blowing I will not feel a draft in that house.

Roger that.

You'd think bigger is better,,,not true in this case. Under sizing is just as bad. Hopefully your new system will have variable speed fans, which will help maximize the efficiency of the new HVAC units.

Glad to be of help

In comment 14476394 afann said:

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I am building a house and went with spray foam. Before the interior walls were up on a windy day you would feel nothing inside. We used 2x6’s on the exterior with 2” of spray foam, leaving room if we needed to get into the walls again. We did have to add, i forget the name of it, a airblower of some sort. We had to do this because the house was so sealed up we needed to get fresh air into the house. It cost $3000. It will force out old air and pump in air from the outside. In our old house I could feel drafts from everywhere..windows, outlets, etc. These guys sealed up every crack in the house. I think on cold winter days when the wind is blowing I will not feel a draft in that house.

Yeah that was my previous house, just a miserable experience. Felt I was running the heat constantly just to fight the cold air blowing through my walls. I need to ask about getting fresh air back in and how that will be handled - still a few weeks away from meeting with the HVAC guy.

In comment 14476186 oghwga said:

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The code officials I used to deal with hated spray foam. They said they'd pass me, but would always prefer fiberglass and the trade off in efficiency for letting a home breathe. Too many times with a less than perfect install they'd see trapped moisture and rot. Make sure your guy is a real expert or you could be in trouble down the line.

I've read that poor installation can result in problems. I think that's par for the course on home upgrades. Shit work gets you shit. I'm going to do my homework on the person that my builder recommends. He did my builders house and he swears by it so that's a big endorsement. Its also a risk/reward situation - will the potential downside be worth the big upside? I'm thinking yes (still need the estimate).